Centrifugal casting machine



F. ELLIS.

CENTRIFUGAL CASTING MACHINE.

APPLICATION FILED APB. I3. 1921.

1,436,756. PatentedN0v.28,1922.

-Fiwt Z0 Patented Nov. 28, 1922.

FRED ELLIS, OF SALEM, OREGON. V

CENTRIFUGAL CASTING vIMACHINE.

Application filed April '13, 1921.

T 0 all whom- ?It may concern Be it known that .I, FRED Ennis, a citizen of the UnitedStates, and resident of Salem, county of Marion, and State of'Oregon, have invented a new and useful'Centrifugal Cast-- ing Machine, of which the following is a specification.

The present invention relates to improvements in centrifugal casting machines such as are principally used by thedental profession in casting inlays, clasps. crowns, bridges, saddles and the like and its object is to present an improved casting machine in which the actual laws of nature with reference to centrifugal force are more closely observed than in the present casting machines and more satisfactory results; obtained thereby. A further object of the invention is to provide a centrifugal casting machine 'in which the rotating shaft is pivotally mounted in the spring-actuated means for rotating it so that the shaft may continue to spin after the tension of the spring has been exhausted. Further objects and advantages will appear as the description proceeds.

I attain these objects by means of the mechanism illustrated in the accompanying drawing. in which Figure 1 represents a plan view of my device. Figure 2 avertical crossscction through the same along line 11-11 of Figure 1. and Figure 3 a horizontal section through the same along line llIIII of Figure 2.

Referring to the drawing in detail thereader will see that in my centrifugal casting device the shaft 1 is arranged centrally within and co-axially with the cylinder "2 rigidly secured to a base plate 3, which latter is adapted to be fastened to a support, as a table for instance. by means of the screws 4. The shaft is pointed at the bottom and its point is resting on the base plate. A horizontal plate 6 extending through the cylinder and secured to the wall of the same, as shown at 7, is provided with a central perforation 8, which. together with a vertically alined perforation 9 in the top plate 1 l removably secured to the cylinder as shown at 12. holds the shaftin a vertical position. Rotary motion is imparted to said shaft by means of the coil spring 14, one end of which is secured to the wall of the cylinder by means of the screw 16 while the other eiid is screwed to a sleeve 17 on the shaft l by means of the screw 18. T he sleeve 17 is rotatable on the shaft and is supported on Serial No. 460,899.

acollar 19 rigidly secured to the shaft. A second sleeve 21 is secured to the shaft 1 immediately above the sleeve 17 by means of the set screw '22-. The two sleeves 17 and 21 are arranged withreference'to each other so that the upper may rotate on the lower in one direction but not in the other. I accomplish this object by means of the ball 23 which is adapted to disappear altogether in a vertical recess 24 in the bottom of the upper sleeve 21. so that ordinarily it would not interfere with the rotation of the upper sleeve on the lower one. but would only rest on the surface of the lower sleeve describing acircle on said surface. But on its circular path the ball meets with a recess 26 in the top of the sleeve 17. The latter recess occupies only a small part of said circular path, starts with an inclining plane and grows deep enough to take up a considerable partof the ball. at the other end. In Figure 2 the ball is shown as being partly sunk into the recess of the lower sleeve. If the shaft 1 is turned clockwise, the upper sleeve 21, being keyed to the same by the set screw, will rot-ate with the same and carry along the ball, which, as shown in the drawing. will on this rotation sink a. trifle deeper into the recess in the sleeve 17 until it reaches its end. Then it will carry the sleeve 17 along and cause the same to rotate and thereby wind the spring. When the spring is released by the tripping device to be described hereinafter, it will cause the lower sleeve 17 to rotate counter-clockwise and the ball, being actuated by the same end of the groove it was hearing on before, causes the upper sleeve to partake of the rotation of the lower one. When the tension of the spring is exhausted the latter will act as a brake on the lower sleeve 17. causing the same to stop rotating. But this brake action of the spring will not interfere with the rotation of the upper sleeve of the shaft, because. when the lower sleeve stops. the ball is at liberty to ascend the inclined plane in the lower sleeve and disappear in the upper sleeve altogether, thereby enabling the upper sleeve and the shaft to spin until the rotary force imparted to the same by the spring action is completely spent.

Underneath the collar 19 there is supported on the shaft a ratchet wheel 3! adapted to he engaged by a pawl 32 extending into the cylinder from the outside and pivoted between two lips 33 extending from the outer surface of the cylinder. The pawl is adapted to lock and release the ratchet wheel and thereby the spring by being swung on its pivot 35.

The shaft 1 extends beyond the top plate 11 of the cylinder and carries at its upper end a horizontal bar 36, secured thereon by means of two nuts 37. The two arms 38 and 39 of said bar extend into opposite directions. The latter carries the casting device, while the former, 38, carries a counterweight ll adj ustabl y secured thereto by the stud 42 extending through a slot 43 in said-arm and' held in place by a nut 44.

The casting device itself is carried by the extreme end of the other arm 39 and con priscs the cylindrical ring 46, known in the particular art as the flask, held in the flask holder 47 and the crucible 45. The flask holder is adjustably fastened to the arm by mcans of the bolt 4 and nut 49, a slot 51 in the arm allowing of longitudinal adjustmenl. Thc crucible is seated in the channel 52 which latter is slidably fastened to the arm 39 by means of the clasp 53 projecting from the bottom of the channel. The theory of this arrangement is well understood in the art concerned. The flask holds the mold and the crucible holds the material to be molded. as gold for instance. The latter is melted by means of a blow-pipe, whereupon the spring is released, which violently rotates the shaft and the two arms and forces the melted metal by centrifugal force into the mold through an aperture 54 in the crucible.

()n closer observation it will be found, however, that this arrangement alone does not utilize the laws of nature concerned to their best advantage. Assuming that the casting device is set as in Figure 2, a mold being arranged in the flask and the crucible provided with the necessary amount of molten metal. \Vhen the shaft commences to rotate now, it will be easily seen that there will be no immediate tendency of the molten metal to be thrown into the mold by centrifugal force. Its first tendency will be to follow the law of inertia and to rise on the rearward surface of the crucible and it is not until after the centrifugal force is fully developed that the metal begins to flow into the mold. Thus a most precious unit of time is lost before the metal begins to flow in the right direction and to overcome this undesil able feature of the present day casting device. I introduce my elbow 56 into the arm. This elbow allows that part of the arm 39 carrying the casting device to pivot on a pin 57 through a quarter turn in a direction opposite to the rotary direction of the arm at the time the casting is done, as shown in full lines in Figure 1. It will be seen that in this manner the direction of the connecting channel between crucible and mold is changed from a radial one to a tangential one and that this direction becomes radial only under the influence of the centrifugal force of the rotating arm. Under this arrangement the connecting channel is made to follow substantially the same laws that the molten metal has to follow, and the tcndc-ncy of the molten metal will be toward said path at the very start of the rotation.

I elalm:

In a centrifugal casting machine, a base, a vertical cylinder mounted thereon. a vertical shaft centrally supported therein, a sleeve rotatably mounted on the shaft, a spring for actuating the sleeve, a second sleeve rigidly mounted on the shaft in sliding contact with the first sleeve, two co-acting recesses in the contacting surfaces of said sleeves, a ball capable of vertical movement in the upper recess adapted to operatively engage the lower recess when rotating in one direction and idlingly when rotating in the opposite direction so as to prevent and allow, respectively, sliding motion between the sleeves, whereby the spring actuated sleeve may actuate the second. sleeve but not stop the same, a ratchet wheel mounted on the shaft within the cylinder and a pawl mounted outside of the cylinder and extending through a slot in the cylinder in engagement with the i ratchet for holding the spring under tension and for releasing the same when manually actuated.

FRED ELLIS. 

